ARTIST-TURNED-film director Fred Keleman is as glacially reserved in person as his beautiful, bleak films would suggest. One would have thought he had little reason to be glacial with the kind of praise he's been getting lately. Pundits in his native country have rightly dubbed him "the most spectacular force in Germany since Fassbinder". Werner Herzog has virtually anointed him his heir. And of his first feature film, Fate, Susan Sontag wrote "[it] is a visionary, one-of-a-kind achievement" and went on to list the 34-year-old German as one of only three directors in the world capable of expanding cinema as an art form.

In fact, Keleman has every reason to be glum. He's currently a combatant in a war zone. Not many months after this ringing endorsement by America's most impressive grande dame (the NYC Museum of Modern Art has since acquired a print of Fate for its collection), he found himself in a situation which is probably the worst thing that can ever happen to a director-auteur. After a catastrophic falling-out with producer Bjorn Koll during the filming of his second feature, Frost, Koll impounded the negative and denied Keleman all further access to it. Keleman had lost actual physical possession of his own film

Koll's behaviour ever since has been somewhat shocking. Despite attempts by the Goethe Institute and MOMA to intervene, Koll has rebuffed all attempts to settle the matter amicably and seems to be conducting a personal vendetta against Keleman. A Koll-edited version of Frost has even been offered to the major film festivals, according to Keleman. And he has received only 10 per cent of his fee, admitting he was so broke during the filming, he went short of food ("I got very hungry," he says, clearly embarrassed to admit it). Not since Eisenstein had his most personal and most experimental film, Que Viva Mexico!, stolen by its American financier in 1932, has there been such a parallel. So where did it all go wrong?

I first met Fred Keleman last November, leaning against the wall in the crypt of St Martin-in-the-Fields, looking much like a big, trenchcoated ghost who had stumbled in on some revelries he didn't quite want to understand. There was something very isolated about him. It was a party in honour of Festen- director Thomas Vinterberg; Vinterberg was the toast of the London Film Festival and was lapping it up. Keleman - I was later to discover - summarily dismissed the Dogme philosophy as "a schoolboy joke, a game", and went so far as to say he had already made a Dogme film even before the playful Danish primitivist diktat was first postulated (Fate out-Dogmes Dogme: it is shot on hand-held camera, in only 12 long sequences over 80 minutes, without music, using only natural light and with no scripted dialogue).

The screening of Keleman's Frost in his own disintegrating "director's edit" (i.e. the print that has been physically chopped and spliced and edited) was actually the most significant moment of the Film Festival: the film had already received the International Critics' Prize at the Rotterdam Festival and had acquired an almost legendary status by the time it reached London. It was a samizdat, fugitive film: every time Keleman showed it the print disintegrated a bit more and the edits grew further apart. Here was a film physically decaying before the audience's eyes, the celluloid slowly and distinctively rotting away. It was a memento mori to send a shudder down the spine of every film director in the world.

The innately pessimistic Keleman, however, expresses little surprise about the way things are: his films, anyway, are largely concerned with human cruelty, thwarted passion leading to abject humiliation, and the deadening melodrama of despair. Fate concerns a Russian busker in the Berlin subway falling into a murder; Frost concerns a mother and young son trudging across a wintry countryside and being preyed on by low-lifes (leading to a murder); his recently completed third feature, tentatively called Nightfall, portrays an unemployed man and wife brutalised by their "barbaric surroundings".

"I think our world is cruel," he tells me when we met again just recently, the fate of Frost still bitterly unresolved. But he refuses to give up. "When I hope, I wake," he says. "When we stop hoping, we fall asleep and can be killed very easily." He has the crumpled but defiant air of a man who has survived every bone in his body being broken by his enemies: he wearily anticipates the inevitablity of pain. He's shabbily dressed and is very shy indeed. His face is flat and uncannily white, his hair a little greasy in the way of the recluse. Serious-minded as ever, and as if to put everything in perspective, he suddenly remarks: "Cruelty is everywhere - just look at the war going on."

I am struck, I tell him, by how the blasted landscapes in Frost resemble those of Soviet war movies so strongly. The characters seem to be moving across a zone where, you suspect, a war is going on. "We filmed on the border of Poland and there were still old tank-traps there," he confirms in his low, halting monotone. "For many years now I've felt there's a smell of war in Europe. I was filming Fate back in 1993 when the war in Chechnya broke out. As you can imagine, it affected my main actor, Valerrij Fedorenko, an opera singer from Chechnya, very strongly. When he wades into the fountain and you see the faces of children in the water, it came from that."

Keleman's antennae are more than usually attuned to the political currents of Eastern Europe: his father is German-Russian, his mother Hungarian, and he spent much of his childhood in Budapest. "Growing up in Berlin, too, while the wall was still there, instilled a sense of unease in me," he says. His pitched battles with the school authorities from the age of 10 also fixed a rebellious streak to his nature and a hatred of patriarchal institutions (tellingly, his father abandoned his family when Keleman was four).

It seems he's no stranger to fights over edits. When defying his tutors at film school over the editing of his graduation film, they brought in Werner Herzog to tame him; unfortunately, Herzog backed Keleman against his teachers. Plus ca change. Keleman, so mild-mannered to meet, surely far too haunted and introspective to be a threat to anyone, is fierce and resolute in the defence of his vision. It's rather refreshing. He really is prepared to starve for his art, as he did with Frost. And fight for it.

Will the wrangle over Frost ever be resolved? The world deserves to see this extraordinary film. Nursing the heavy-hearted air of a war poet waiting for a war, Fred Keleman is a man to watch, a Dante for the millennium whose visions of hell on earth have a gravid and spectral authority few can match.